Variable-pitch propeller for airplanes



. I c. L. PARKER VARIABLE PITCH PROPELLER FOR AIRPLANES Filed Dec. 15, 1922 'I Sheets-Sheet 1 WITNESSES ATTORNEY Dec, 16, 1924.

C. L. PARKER VARIABLE PITCH PROPELLER FOR AIRPLANES Filed Dec. 15 1922 7 Sheets-Sheet 2 N'roR,

WlTN ESSES ATTORNEY,

Dec. 16, 1924. Y 1,519,163

. C- Li. PARKER I ARIABLE PITCH PROFELLER FOR AIRPLANES Filed Dec. 15 1922 7 Sheets-Sheet 4 INVENTOR,

s E s S E N w w c. L." PARKER VARIABLE PITCH PROPELLER FOR AIRPLANES 7 Sheets-Sheet 6 Filed Dec. 15 1922 INVENTOR,

ATTORNEY Dec. 16, 1924.

c. PARKER VARIABLE PITCH PROPELLER FOR AIRPLANES Dec, 16, 1924.

' Filed Dec. 15 1922 7 Sheets-Sheet INVENTOR} ATTOR N EY .be firmly Patented n... is. 1924.

UNITED STATES. PATENT OFF ICE.

01443311103 LYKAN PAR-KER, OF LOS ANGELES, CALIFORNIA.

VAR IABLE-PITCH PROPELLER FOR AIBPLA NES.

Application filed December 15, 1922. Serial .No. 607,116.

use on airplanes, and which is in the nature of an improvement" on the structure shown and described in Letters Patent N 0. 1,386,274, issued to me August 2,1921.

The variable pitch propeller permits a more rapid get away as well aspermitting the proper adjustment tosecure the best results in accordance with the speed at which the machine is traveling, as well as varying atmospheric conditions. It also permits the blade to be thrown into reverse and utilized as an air brake to stop the machine within a very much smaller distance than would be possible. with the old type of propeller.

One of the important objects of the present invention is to provide an improved construction-by which the propeller blades are connected with the sockets which are secured to. the propeller shaft, whereby the same will withstand the powerful centrifugal force developed when the airplane is traveling at great speed, at the same time permitting the action of the airplane accura structure. 7

free movement of the blades about their axes to vary the pitch thereof.

Another object of the invention is to provide improved means. for controlling the variations in pitch from the cock-pit, whereby the aviator may know accurately the posi-tlon of adjustment and thereby control the tely at all times. With the above and other minor objects in'view, which will be understood as the description proceeds, the invention consists in certain details of construction which will be described in connection with the accompanymg drawings forming a part of this specifi-' cation.

In thedrawin v Fig. 1 1s a si e elevation'of the forward end of the fuselage showing the pro an 1 3 Fi 2 is a connected with plan view ofthe Invention Fig. 3 is a sideelevation of the operating wheel and dial.-

wedged therein so as toefi'ectively a portion'of the airplaneand provided inside the b Fig. 4 is a lon itudinal section throughthe forward end 0 propeller.

Fig. 5 is an end view of the propeller blade basebefore it is applied. I ig. 6 is a side elevation of the same. Fig. 7 is an end elevation of the same partly'inserted in the ferrule.

Fig. 8 is aside elevation of the same with the ferrule shown in section.

Fig. 9 is a detail perspective view of a taper wedge which isa part of the invention.

the engine shaft and the Fig. 10 is a longitudinalsection at right angles to the plane of Fig. 4.

Fig. 11 is an end elevation of a part of the controlling means.

1 Fig. 12 is a section on the line 12-12 of Fig. 4.

Fig. 13 is a. section through the socket and sleeve, taken on the same plane as Fig. 4.

Fig. 14 is a cross section on the line 14-44 of Fig. 10.

Fig. 15 is an end elevation of the parts shown in Fig. 14.

Fig. 16 is a section taken through the propeller blade base but showing a modified form.

Fig. 17 is a view similar to Fig.f16 but showing another modification.

Fig. 18 is a longitudinal sectional view of the taper wedge as used in the form shown in Fig. 4. I

Fig. 19 is a longitudinal section through the rear end of the propeller shaft showing a modified construction. I

Fig. 20 is a cross section taken on the line 20 20 of Fig. 19.

Fig. 21 is a .view similar to Fig. 19 but showing another modification,

Referring'more specifically to the draw ings, 1 indicates the-body orfuselage of an airplane having at its forward end a radiator 2 which may be of the usual construction. On the outside of the airplane bod is secured a pair of brackets 3 and 4, pre

erably by means ofbolts which pass through one of the corner beams 6 of the frame. Said brackets form bearings for a lon itudinal shaft 5 by the rotation of which t e pitchof the propeller blades may be varied. through the medium of mechanism which.

which will be hereinafter described.

The rear end of the shaft 5 is connected by bevel gearing 7 with a stub shaft 8 extendingtransversely thI'OliFh the beam-6,-*

y with a'driven sprocket wheel 10, which is connected by a sprocket chain 11 with a drive sprocket wheel 12, journalcd on a stud 13 formed on a bracket 14 that is secured to a perpendicular post 15 at one side of the cock-pit.

(Figs. 2 and 3.) The sprocket 12 is of considerably larger diameter than the sprocket 10. Said sprocket 12 is provided with a pair of converging arms 16 and 17 which extend beyond the periphery of the sprocket and constitute a crank in the form of a frame, having at the outer end a handle 18, by means of which the adjusting mechanism maybe manipulated. The arms 16 and 17 have secured thereto a brace 19 from which a pointer 20 extends inwardly toward the sprocket over a dial 21 which is fixed to 'the beam 6 and is provided with indicia to indicate the pitch ofthe propeller blades which corresponds to the position of the sprocket 12. .The dial is of a greater diameter than the sprocket, as shown in Fig. 3, so that the figures on the dial are visible at the side beyond the periphery of the sprocket. r, The numbers on the dial increase from the zero point in both-directions to indicate forward and reverse. By this arrangement, the operating handle and the pointer are both carried by the drive sprocket, and the-operator may keep an accurate watch on the movements of the pro peller blades'through the dial. The mounting 7 of the driving device on the larger sprocket, and the relative arrangement of the pointer and dial, the pointer being carried by the movement of the sprocket, constitutes one of the improvements made over my former patent. Moreover, the mechanism enables the blade to be rotated in either direction, which is not the case with the operating mechanism of my former patent.-

The forward portion of, the crank shaft 22 is journaled in ball bearings 23 in the.

forward part of the engine frame 24, as seen in Fig. 4. The crank shaft is preferably made hollow for the sake of lightness,

and has its forward end tapered, as at 25,

and provided with a key seat 26 for the receptlon of a spline 27. which is secured to the tapered extremity by means of set screws' 28. This provides a seat for the tapered bore of the hub 29, in which the bases of v the propeller blades are mounted. Mounted on the shaft 22 is a sleeve 29*, interposed between the hub 29 and the ball bearings 23, the sleeve being recessed to receive a packing 29 On the otherside of the ball bearings is a spacing sleeve 29 which is fitted to the shaft 29.

The tapered end of the shaft has a reduced screw-threaded extremity 30 that receives a hollow'nut 31, the head'of which is "provided with a peripheral flange 32. Inside the flange 32. and surrounding the nut 31 is a jamb nut 33 whiclris threaded into the outer end of'the hub 29, as shown at 34. The flange 32 and the head of the jamb nut 33 .are preferably provided with slots 35 or similar means for the application of a suitable tdol. The outer side of the hub is flattened as shown at 34 to form a suitableseat for the nuts 31 and 33.

As best shown in Fig. 13, the hub 29 is provided with a number of laterally-e'xtending sockets 36, according to the number of propeller blades to be used, and each socket is provided with an internally threaded .outer'end 37,, which receives the reduced end'38 of a sleeve 39 shown in Fig. 4. The sleeve39 is provided with an annular shoulder 40 which is adapted to abut against the outer end of the socket '36, and at its outer end the sleeve is reduced as at 41 to receive roller stress bearings 43,

an inwardly directed flange 42, which is spaced from the outer end of the sleeve, forming a part of the housing for sa d bearings. Revolubly mounted in these bearings 43 is the inner reduced end 44 of a ferrule 45, which receives the inner or butt portion of the stem 46 of the propeller blade. The blade at a point removed from Y the butt end is reduced in width and is formed with an'incline'd shoulder, and from said shoulder the butt portion begins to increase in width by a gradual taper, thereby defining a butt portion which is substantially dovetail in shape (Fig. 4). At the smaller end of the reduced portion the diameter is four inches, and it increases in diameter to 4% inches, which is the size at the larger end.

In the structure shown in Fig. 4, the in -termediate inclined portion or shoulder 47 of the ferrule forms a seat which rests on the shoulder of the butt end of the blade and has openings through which lag screws 48 are inserted obliquely intothe stem 46 to furnish additional security in holding the ferrule in place. A ring 49 forms the outer housing for the :roller bearings. The

ring is preferably .=forinedin sections and rests .on. the shoulder 47 of the ferrule,

-and is held in place by the outer end of the Secured bearings 54 which bear against a flange 55,

formed on the inner end of the sleeve 39. This ferrule section 51, as will be readily understood, forms an outwardly tapering the sleeve 39 to provide a part of 'ing for the stress bearings 43.

surface against which the propeller blade base will be firmly engaged to' prevent the blade from being displaced when it is rotating at a high rate of'speed. As Fig. 4 shows, the outer section of the ferrule extends beyond the shoulder of theblade and embraces the blade for a short distance.

The manner of inserting and securing the propeller in the ferrule will be best understood by reference to Figs. 5 to- 8, inclusive. The propeller blade is first cut in the shape shown in Fig. 6, with the inner or butt end flared outwardly. A central tapered hole 56 is bored axially into the end thereof; and

radial V-shaped slits 57 are cut, from the hole to the outer side and extend from the butt end nearly to the shoulder of the blade, in order to )ermit the end to be sprung inwardly, as shown in Fig. 8. base has been inserted into the ferrule, the segments58 defined by the slits are spread outwardly by the insertion through the hole 56 of a taper wedge 59 which is hollow. and has longitudinally tapered fingers 60, Fig. 18, which urge t 7 against the wall of the ferrule. A hollow stem 61, of substantially the same length as the wedge, is then forced into the bore of the wedge 59. The inner portion of the wedge 59 is provided with a rounded reduced end 62 which extends beyond the butt end of the blade and forms a pivot which is rotatably mounted within one of the holes 63 in the hub 29. This is one of the novel features of this invention. Two or more of these holes 63 may be provided, ac-

cording to the number. of propeller blades to be used.

The inner end of the propeller blade base further secured within the ferrule 50 by the insertion of flat wedges 64 into the slits 57. (Figs. 4,9 and 12.) The inner end 65 of each of the Wedges 64 is reduced in width to correspond,with the decrease in the diameter of the ferrule, and the outer edge 66 isthicker than the inner edge to correspond with the greater expansion toward the periphery of the segment. .It follows that the Wedges 64 are tapered both laterally and longitudinally. This is another novel feature of this invention. The Hat wedges are inserted into the-slits simultaneously after the ferrule has been applied and after the wedge 59 and the stem have'been pressed into place. Glue may, if desired,

he applied to the butt and wedges before the latter are pressed into place.

-Annu'lar ribs 50 extend out from the ferrule for strengthening the same, one of the ribs cooperating with flange 42 formed on the -ho us- Eachof'the sockets '36,, is provided near its base with a peripheral slot 69, and secured to the collar After the bladehe segments 58 outwardly the forward end of v splined connection 88 therewith.

52 opposite this 'slot'is a plate 67 having which is pivoted a link 70, the other end of the link being pivoted betwen the ears 71 of .a link arm 71, which is rigidly secured at its other end to an annular flange 72, formed on a ring 73, supported by ball bearings 74 for rotation, but heldagainst movement longitudinal to the direction of the propeller shaft. Figs. 10, 11 and 12.) The arm 71 'is extended beyond its pivotal connection to form a nose 75, by means of upstanding ears 68 to which it is guided in its movement. The

intermediate portion of the arm 71 is guided in a slot 76 formed in a bracket 77, which is formed integral-with the socket 36. (Fig. '14.) The ball bearings 74 are supported by a bearing ring 78, which is secured to a collar 79 having a square threaded connection 80 with a sleeve 81, which is fixedly secured by means of a flange 82 or other. suitable means to the engine frame 24.

Figs. 19, 20 and 21 show modifications of this connection. In order that the .sleeve 81 may fit up-close to the hub of the propeller, the latter is flattened as at 81., (Fig. 13). It will be understood that the rotation of the collar 79 will cause the same to move longitudinally of the shaft along the screwthreaded sleeve 81, and thereby rock the propeller blades on their axes to change the pitch thereof; In order to effect this movement, the collar 79 is formed with an integral sprocket wheel 83 which is connected, by means of a sprocket chain 84,

to a sprocket wheel 85 on the forward end of a hollow shaft or sleeve 86, (Figs. 1 and 2). This sleeve has a screw-threaded connection 87 with the bracket 3, so that as'the sleeve is rotated to advance the collar 79' and sprocket wheel 83 to alter the pitch, the sprocket 85 carried at the forward end of sleeve- 86, will also be advanced and will althe same plane with the The sleeve 86 telescopes shaft 5 and has a Thus, whenever the sprocket wheel 12 is rotated, a positive and definite movement is trans-. mitted to the propeller blades. .In the modification shown in Fig. 16, instead of the propeller blade base having a bearing in the hub 29, I have inserted inthe opening 63 of the hub the reduced cir-, cular end 89 of a boss 90, to which is secured a circular plate 91 having at its periphery a wear plate 92 for receiving bearing rollers 93, a cup-shaped housing 94 being secured to the plate 91 by rivets 95 or the like. 1e inner end 51 of the ferrule is provided with. a wearing ring 96, and the inner end of the blade base provides an inner housing for the rollers 93. In this form, the taper Ways remain in sprocket wheel 83.

Lwedge 97 may be made in one integral piece,

' bore 102 being merely reducing the weight. is a direct pivotal connection between the,

a' bearing for the bushing for an airplane having a rotary engine.

boss98 is secured in one of the openings outer end forms 99,'\vhich is secured within a bore at the outer end of the taper-wede 100. In this case. 'the taper wedge is .ioredlfrom each end, one bore 101 forming a bearing socket and the other for the )urpose of In this orm, there 63 of the hub 29, and its hub. In both forms shown 17, the fiat wedges 64 are em wedge and the in Figs. 16 and ployed.

In Figs. 19 and 20, I have shown a form of connection which is especially adaptpd n this connection, the propeller shaft 103 is connected by a flange coupling 104: to the shaft of the engine, and between the flange 10-l and the hub 29, roller bearings 105 arev provided for supporting the propeller shaft within the sleeve 106, the latter being secured by braces 107 from the hood cover 108. The sleeve 106 of this figure is like sleeve 81 of Fig. 4:.

The modificatidn shown in Fig. 21 is 'of the same type as Fig. 4, but showsthe threaded sleeve 109 (like sleeve 81) threaded into a flange 110 formed on the forward part of the engine frame 111, and'secured ina fixed position of adj ustincnt by means of set screws 112.

From the foregoing description, it will be seen that I have provided a means for ,0 connecting the propeller blade base or butt portion to the socket in the hub so that the segements 58 thereof are firmly held both radially and circumferentially, whereby to withstand the centrifugal force developed by the rotation of the propeller. At the same time, the propeller blade is held against lateral stresses by the roller bearings 4.3, and against end thrust by theroller bearings 53, so that changing of the pitch may be accomplished with' the greatest facility regardless of the speed at which the airplane is traveling. The pitch of the propellers may also be quickly read from the dial 21, and the blades may be adjusted for greater'speed ahead, or may be adjusted to areverse position when'landlng.

I have shown and described the details -of-what are atpresent the preferred embodiments of myfinvention, but it will'be understood that various other changes and modifications may be made therein within the scope of what is claimed without departin from the principles of the invention.

at isclaimed is:-

' 1. In'an airplane, the combination with "*zrfuselage, a propeller shaft and propeller gitudinal shaft on blades capable of blades, of a mechanism for varying the pitch of the propeller blades and including a 1onthe outsideof the fuselage, a rotatable element within the fuselage and operatively connected with said longitudinal shaft for actuating said mechanism, a frame mounted on said rotatable element and carrying an operating handle and a pointer, and a dial mounted in a fixed position concentric with the rotatable element and larger than the same, whereby the pointer will indicate on gree of pitch of the blades.

2. In an airplane, the combinationwith a fuselage, a propeller shaft and propeller blades, of a mechanism for varying the pitch of the bladesso as to-imp'el the airplane forward or backward at different speeds, including a longitudinal shaft on the outside of the fuselage, a stub shaft geared to the longitudinal shaft and extending through the side of the fuselage and having secured .to its inner end a rotatable element for actuframe mounted on ating said mechanism, a said rotatable element and extended beyond the periphery thereof, a handle carried by the frame, a pointer also carried by the frame and extending inwardly toward thecenter of the rotatable element, and a dial of greater diameter than the rotatable element and concentric therewith, so that the figures thereon will show beyond the periphcry of said element to indicate the degree of positive or negative pitch of'said blades. 1

3. In an airplane; blades capable of being longitudinally of and individual to the blades. a shaft carrying the propeller, mechanism for varying the pitch of the blades including a longitudinal shaft mounted on the outer side of the fuselage. means connecting the shaft to theblades. a drive sprocket on .the inside of'the fuselage and operatively connected to the longitudinal shaft. a frame mounted on the drive sprocket and carrying an operating handle and a pointer. and a fixed dial concentric with the sprocket and larger than the same, whereby the pointer will indicate the degree of pitch ofthe blades. A

4. In an airplane. a propeller having being rocked about axes a propeller having rocked'about axes the dial the de longitudinally of and individual to the blades, a shaft earry-ing the propeller. an mechanism for varying the. pitch of the blades, said mechanism 'including a pair of sprocket wheels connected by a sprocket chain, means connecting said sprocket wheels to the blades, the larger of said sprocket wheels being the drive sprocket. a frame mounted on the drive sprocket and'carrying an operating handle and a pointer, and a dial mounted in a-fixed position at one side of the drive sprocket and larger than the blade, a

. having its end ing the bore,

same, whereby the and extended beyond the periphery thereof,

a handle carried by the frame, a pointer also carried b the frame and extending inwardly towandt e sprocket, and a dial of greater diameter than said sprocket and arran ed at one side 5 of the same so that, the gures thereon will show. beyond the periphery of the sprocket, the pointer movln over the dial face as the sprocket is rotate by grasping said handle.

6. In an airplane, a propeller having blades capable of b6111 rocked about axes lon itudinal of and individual to theblades, a s aft carryingthe propeller, a threaded sleeve surrounding the shaft, a collar threaded on the sleeve, means accessible to an 01perator for rotating the collar about t e sleeve, and connections between the collar and the blades and tangentially, said connections including a link and a link arm pivoted thereto, said link arm being extended beyond its ivotal connection to' form a nose by whicli it is guided in its movements.

7. A propeller for airplanes comprising a blade, a ferrule for the butt end' of the blade, said blade having a central bore extending inwardly from its butt end, and a 'wed e enteri the bore from the butt end, sa1d wedge having its end projecting from the bore beyond the butt end of the blade and constituting a' pivot for the blade.

8. A propeller for airplanes comprisinga blade, a ferrule for the butt end of the blade, said blade having a central bore extending inwardly from its butt end, and a wedge entering the bore from the butt end, said wedge being radially expansible and adjacent the butt end of the blade constructed to constitute a pivot for the blade.

9. A propeller for airplanes comprising a ferrule for the butt end of the blade, said blade having a central bore extending inwardly from the butt end, a hollow wedge having longitudinally tapered fingers enterand a stem driven into the said-wedge to expand the fingers outwardly.

10. A propeller for airplanes comprising I a blade, a ferrule for'the butt end of the blade, said blade having a central bore extending inwardly from the butt end, a hollow expansible wedge driven into said bore from the butt end, and a stem driven into said hollow wedge.

' 11. A propeller for airplanes comprising connected to the latter and means having its butt end a blade, :1 ferrule for the butt end of the blade, said blade having a central bore extending inwardly from the butt end, a hollow 'expansible wedge drivenv into said bore from the butt end, and a stem driven into. said hollow wedge, sa1d wedge and sa1d stem being of substantially the same length and the stem being hollow.

12. A propeller for airplanes comprising a blade, a ferrule for the butt end of the blade, said blade-having a central bore extending inwardly from the butt end, a hollow expansible wedge driven into said bore from the butt end,and a stem driven into said hollow wedge, both the wedge and the stem being extended beyond the butt end of the blade, and jhe wedge being constructed to constitute a pivot for the blade.

13. In combination with a hub having-a series of openings, a series of propeller blades, each blade being provided with. acentral wedge having its end rojecting from the butt end of the blade and constituting. a pivot which is received within one of said openings.

14. In combination with a hub having an opening, a pro eller blade having a central bore, a wedge tted in said bore, and means cooperating with said wedge and fitting in said openlng to constitute a pivot for the blade. h

15. In combination with a hub having an opening, a propeller blade having a central bore, an expansible wedge fitted in said bore, meansaotin to forcibly expand the wedge,

located at the butt end of the blade and fitting in said opening to constitute a pivot for the blade.

16. In combination-with a propeller blade having its butt end reduced in diameter to define a shoulder, and beyond said shoulder increasing in diameter and flaring outwardly,-and a ferrule fitting said butt end and the shoulder, and screws enterting the ferrule and the blade at the shoulder thereof.

'17. In combination witha propeller blade provided with a shoul- IOU Ill)

der, and a. ferrule fitting said butt end and also formed with a shoulder to fit the shoulderof the blade, and screws passing through holes in the shoulder of the ferrule and entering the blade.

18. In combination with a propeller blade having its butt end. provided with a shoulder, a ferrule fitted to the butt end of the blade and the shoulder and formed of two sections detaehably connected together at the shoulder.

19. In combination with a propeller blade having its butt end provided with a shoulder a ferrule fitted to the butt .end of the blade and theshoulder'and formedof two sections detachably connected together at the shoulder, the outer section extending outwardly along the blade beyond the shoulder.

20. In combination with a propeller blade dovetail shape,

shape to the butt portion of-the blade and having its butt end having at a point removed from its inner or butt end a shoulder formed by a reduction of the diameter of the-blade, and from said shoulder expanding outwardly into a ferrule corresponding 1n embracing the same including the dovetail portion, the shoulder and that portion of the stem of'the blade outwardly from the shoulder, and an axial wedge in said butt end to wedge the same against the ferrule, said wedge having its end ad acent the butt end of the blade constructed to constitute a pivot for the blade.

21. In combination with a propeller blade havin its butt .end provided with a shoulder, a ferrule fitted to the butt end of the blade and formed of" two sections detachably connected at the shoulder, a sleeve embracing the ferrule; and a ball bearing located at the shoulder and held between the outer end of the sleeve and the ferrule where the two sections are joined; a

22. In combination with a propeller blade provided with a shoul' der, a ferrule fitted tothe butt end of the blade and formed of twosections detachably connected at the shoulder, a sleeve embracing the ferrule, a'ballbearing located at the shoulder and heldbetween the outer end of the sleeve and the ferrule where the two sections are joined, and a ring cooperating with the sleeve and ferrule for holding the ball bearing in place.

23 A ropeller for airplanes comprising a blade raving its butt end'provided with a central bore, and radial slits extending slits,

1 a blade, a blade,-said and radial V-shaped slits extending inlaterally from the bore to the outer side of said butt end, a wedge entering the bore from the butt'en'd, a ferrule for the butt end of the blade, and separate wedges for each radial slit. i

. 24. In ia. propeller for airplanes, the com-- bination with a ferrule tapered from its inner end toward its outer end, of a propeller blade having its base in said ferrule, said base having a central bore and radial and circumferentially, the wedge in sal borehavlng a bearing surface onwhich the blade is rotatable to vary the pitch.

25., A propeller for airplanes comprising butt end having acentral bore slotted wed ge and-wedges in said bore and slits, whereby to wedge said base both radially Intestimony,

vferrulefor the butt end of the a blade, a ferrule for the butt end of the] having a central bore blade, said butt end and radial slits extending inwardlyfrom 'the butt end, a roundt'apered. wedge entering the hore from the butt end toexpand the butt toward the ferrule, and flat wedges cntering'the slits to expand the butt circumferentially.

.27. A propeller for airplanes comprising -a blade. a ferrule for the butt end of the butt circumferentially, said I blade, saidferrule and butt end being tapered from their inner entremity toward the top of the" blade, said butt end having a central bore and radial slits extending inwardly from the butt end, a round tapered wedge entering the bore from the butt end to expand the butt toward theferrule, and

flat wedges entering the slits to expand the butt circuinferentially, the flat wedges being tapered both laterally and longitudinally.

28. A propeller for airplanes comprising a blade. a ferrule for the butt end of the blade, said butt end a round tapered longitudinally entering the base from the butt end to expand the butt toward the ferthe end.

rule, a cylindrical core for said wedge, said wedge and core forming a bearing for the inner end of the blade butt, and flat wedges entering the slits to expand the butt circumferentially.

29; A propeller for a blade, a ferrule for airplanes comprising the butt end of the blade, said ferrule and butt end being tapered from their inner extremity toward the tip of the blade, said butt end having a central bore and radial slits extending inwardly from the end, a round tapered wedge entering the .bore from the butt end to ex pand the butt towardthe ferrule, said wedgefor theinner end of the (1 blade butt, and flat wedges entering the'slits to expand the butt. end circumferentially;

that I claim the foregoingforming a hearing as my own, I have ture.

, @GLARENOE LYMAN PARKER,

hereto afiixed my signahaving a central bore a and radial slits .cxten'dlng inwardly from 

